I just loaded a fresh copy of the pack into an existing project in Unreal 4.23 - off of the Epic server (the same file you have access to).
Here are my results:
Also, you’ll see the same stretching in the texture files on my end:
This is definitely a UV issue. I’m not sure how the UVs got repacked on your end, but they must have somehow. The stretching on the texture files should lie outside of the UV islands, and should therefore not appear on the mesh.
You can double check - your the 4x4ceiling mesh’s UV 0 should look like this:
If it isn’t exactly like that, the texture will not project correctly onto the mesh.
Should be an easy fix, use the Epic launcher to reinstall the pack into your project. Just find the pack in the ‘Vault’ in the Unreal Engine Library. Select “add to project” and then “yes” when if asks you to confirm the overwrite.